Goods such as oil, frozen foods and the like have generally required the transportation and storage of large 55 gallon drums between warehouses, cargo ships, trains and tracks. Standard lifting devices for 55 gallon drums including metal and plastic drums that are used for storing products such as dry goods and liquids, have generally involved forklift trucks and their attachments. These standard lifting mechanisms have numerous problems and limitations. The standard parallel tow piece forks on the forklift can damage the drums. Fork lift type attachments are generally limited to an attachment that grips about the tops of single cylindrical drums.
U.S. Pat. No. 5,236,298 to Lehman only has the capability of lifting one drum at a time with a fork lift. Devices such as the Lehman system also have potential slippage problems since this device does not grip about the indented portions of a drum body and instead tries to broadly grip about the largest outer diameter dimension when lifting. Another problem with the single lift mechanism of Lehman is that the arcuate members are not fixably clamped in place during lifting and can separate during a lift causing a drum to fall and become damaged. Thus, the Lehman system cannot adequately lift conical plastic drums such as the drums described in U.S. Pat. No. 5,390,795, without causing damage to the drums themselves.
U.S. Pat. No. 4,272,220 to Garcia describes a drum lifting attachment for a forklift that is supposed to be able to lift two cylindrical drums. However, Garcia only provides for arcuate arms to be used at the extreme outside edges of the forklift attachment as shown in FIG. 6. In essence, each single drum being lifted is not adequately supported on all sides with the Garcia device. Like, Lehman, the Garcia device also cannot adequately lift conical plastic drums such as the drums described in U.S. Pat. No. 5,390,795 without causing damage to the drums themselves. Furthermore, the Garcia '220 patent does not provide for lifting drums of varying diameters, such that a smaller diameter drum cannot be safely lifted.
In addition no prior art is known to exist to the subject inventors that is capable of lifting four drums simultaneously. Thus, there is a need for a need for drum lifting attachments for forklifts that avoid the problems associated with the prior art lifters referred above.